The trend in designing and fabricating semiconductor integrated circuits is to incorporate more and more individual devices in each integrated circuit. This trend requires such individual devices, and hence the components making up those devices, to be reduced to ever smaller and smaller size. Although the device size is reduced, the concomitant goal is to maintain device performance. This goal requires changes in device fabrication. For example, either polycrystalline or amorphous silicon is often used in the fabrication of semiconductor devices, such as for forming gate electrodes and other device components. Although there is an obvious difference in the crystalline nature of the polycrystalline silicon and amorphous silicon, for convenience herein the term “polycrystalline” will hereinafter be used to mean either polycrystalline or amorphous as the two materials behave in a similar manner in the context of the instant invention. To maintain the requisite conductivity of a polycrystalline silicon gate electrode, interconnect, or other device component, the impurity doping level in the polycrystalline material must be increased. Increasing the impurity doping level in polycrystalline silicon, however, leads to problems with acceptable photolithographic patterning and etching of the polycrystalline component. This problem is exacerbated by the need for ever smaller device and component size. Consider a gate electrode of an MOS transistor as an example. The size of the gate electrode must be reduced, which requires the impurity doping level in the electrode to be increased to maintain adequate conductivity. The increased impurity doping level causes problems in etching the electrode, but the reduced electrode size imposes severe requirements on maintaining electrode size and profile.
Accordingly, it is desirable to provide improved methods for fabricating semiconductor devices including methods for etching impurity doped polycrystalline silicon. Furthermore, other desirable features and characteristics of the present invention will become apparent from the subsequent detailed description and the appended claims, taken in conjunction with the accompanying drawings and the foregoing technical field and background.